Yahoo is hoping to reduce Google's power by allowing other people to build their own search engines using Yahoo's back-end via an API (applications programming interface). This should result in dozens or even hundreds of new search engines targeted at more specific markets or offering innovative interfaces or whatever. Yahoo says:

Our hope is that the resulting expansion in user choice will have the effect of fragmenting the increasingly consolidated search market in much the same way that cable TV dramatically increased programming choices for television viewers.

Yahoo has launched BOSS (Build your Own Search Service) with some examples. These include Me.dium, which includes browsing info, Hakia semantic search, and Cluuz, "a next-generation search engine prototype".

Yahoo also says:

In the coming months, we'll be launching a monetization platform for BOSS that will enable Yahoo! to expand its ad network and enable BOSS partners to jointly participate in the compelling economics of search.

BOSS is free but monetization will, of course, lock you into Yahoo's advertising network. That's the quid pro quo.

Still, I think it's a great move. Each search engine may only attract a tiny market share, but there's a chance that lots of tiddlers can nibble away at the Google shark. And since Yahoo is failing anyway, it doesn't have much to lose. Put it this way: Yahoo Search losing 10% of its audience to tiddlers is not a bad deal if the tiddlers can get 10% of Google's much bigger audience as well.

Whether it will work is another matter. Since I actually believe that tech markets that work competitively tend to lead to "natural monopolies (PDF)," my long-standing belief is that (unless it really screws up) Google will eventually end up with 90% of the search market.

So the real question is whether BOSS is a game-changer in a way that Nutch wasn't, five years ago. Well, is it?